This invention relates to the field of fish finders that transmit signals through the water to locate fish which in turn send back corresponding signals to indicate the location of such fish, and particularly to fish finders that can be used from the bank or shoreline of a body of water.
Prior art devices of which the inventor is aware include those disclosed in the following United States patents.
U.S. Pat. No. 5,260,912 discloses a side-looking fish finder which transmits a sonar pulse approximately horizontally into a body of water and monitors its echo. The time interval between pulses is varied in a random manner to permit two or more similar units to be used in close proximity to each other without significantly interfering with each other.
U.S. Pat. No. 5,253,220 discloses a fish finder comprising a specially constructed rod and reel for electrical communication between a sensor float and a display unit releasably attached to the reel. A transducer is mounted in the float to convert the electrical signals to ultrasonic signals which are directed downward into the water and which receives sound wave echoes from any fish on which the ultrasonic signals impinge, that are then converted back to electric signals for showing on the display.
U.S. Pat. No. 5,182,732 discloses a reversible fish finder drive apparatus which rotates the fish finder transducer back and forth in a preselected pattern in a generally horizontal orientation.
U.S. Pat. No. 5,088,068 discloses a hand held underwater distance measuring device which includes a transducer for lowering about six inches into the water, telescoping tubes leading from the transducer to an electronic signal generating package and to a display unit on which to indicate numerically the distance that has been measured.
U.S. Pat. No. 4,995,009 discloses a castable fish and depth finder wherein a transducer may be cast out on a line from a rod and reel to a selected spot, at which the transducer emits signals downwardly to determine the depth of the body of water at such location as well as any fish that may be in such below the transducer location.
U.S. Pat. No. 4,982,924 discloses a mounting apparatus for a sonar transducer comprising a bracket connected to a boat and a shaft extending downwardly from the bracket at whose lower end a sonar transducer is connected. The shaft and transducer can be raised and lowered as well as pivoted to different positions.
U.S. Pat. No. 4,980,872 discloses a transducer position control comprising a mount for the transducer of horizontal axles journaled by surrounding sleeves on the depending end of a vertical standard attached to a moving boat. The sleeves and axles are interconnected with manual controls by links and universal joints at the end portions of the standard.
U.S. Pat. No. 4,979,153 discloses mounting apparatus for the sonic transducer of a fish finder comprising a tubular control arm and clamp for connecting to the side of a boat and to extend downwardly on a generally vertical axis. A pivotally mounted transducer plate is provided at the lower end for securing the transducer thereto.
U.S. Pat. No. 4,888,747 discloses a transducer control arm assembly for floating and positioning a sonar transducer in otherwise inaccessible positions for fishermen. It includes an articulated boom to extend out from a boat with a transducer directed downward to locate fish below the transducer.
U.S. Pat. No. 4,779,239 discloses a sonar transducer system having an even number of antennae formed from superimposed linear arrays operating alternatively by halves, at each change of direction of rotation, for transmission and reception. The antennae are mutually offset angularly by angles which are mutually equal as well as being equal to the rotary alternating sweep angle to which the assembly of antennae is subjected.